When lifting a heavy weight in accordance with an intention of a wearer, a wearable muscle assistive robot can lift the heavy weight because a force is transmitted from the wearer to the robot and the transmitted force is amplified through the robot. The present inventive concept relates to a method capable of improving sensitivity of a wearable robot for good transmission of intention from a wearer to the wearable robot, that is, for maximum transmission of force from the wearer to the robot.
Wearable muscle assistive robots of the related art have found out the intention of a wearer by means of EMG (Electromyogram) sensors attached on the wearer's body or torque sensors mounted on driving joints of the robots. A method of using EMG sensors is used to drive an actuator by determining, from contraction and relaxation of muscle, signals for the intention of motion of a wearer and then sending the signals to a robot controller. This method has a problem in that when the wearer moves, the EMG sensors are not accurately in close contact with the body so that the signals for the intention of motion of the wearer are distorted in many cases. On the other hand, a method of using torque sensors measures all of torque exerted in the driving joints of a robot and reflects the intention of a wearer by discriminating the torque for driving the joints of the robot from the torque transmitted to the robot from the wearer. However, using torque sensors reduces the durability of a robot and there is a burden that expensive torque sensors are required.
In the related art, JP2000-218577 A, titled “Robot control system’, a robot control system is provided that includes a driving unit position servo means for controlling the positions of driving units of a robot to follow given servo instruction values, provided with a driving unit position feedback loop and a driving unit velocity feedback loop. The robot control system includes: a position error calculation means that calculates differences between position instruction values of the driving units of the robot and the current position of the driving units; a correction amount calculation means that calculates multiplying of the output of the position error calculation means and a position gain correction coefficient set as predetermined value; an addition unit that adds the current positions of the driving units to the output of the correction amount calculation means; a velocity gain correction unit that multiplies the velocities of the driving units of the robot by a predetermined velocity gain correction coefficient; and a correction instruction value calculation unit that calculates a correction instruction value by adding up the output of the velocity gain correction means and the output of the addition means. The output of the correction instruction calculation means is inputted to the driving unit position servo means as servo instruction values for joints.
However, even according to such a technology, it is necessary to know a displacement at the end by calculating a driving value of the robot in advance. Therefore, there is a problem in that the technology did not propose a method of improving sensitivity by finding out the intention of a wearer, when the wearer freely moves, without finding out the displacement and using separate sensors in a wearable robot.
The description provided above as related art of the present inventive concept is just for helping understanding the background of the present inventive concept and should not be construed as being included in the related art known by those skilled in the art.